1. Field of the Invention
This invention relates to a photographic film assemblage including a film cassette for housing a battery and a plurality of sheet-like members including several film units, and more particularly to means for electrically insulating the battery terminals from engagement by a pair of camera mounted contacts in response to removing the last sheet-like member from the film cassette.
2. Description of the Prior Art
Manufactures of photographic equipment are continually striving to automate certain functions which were previously performed by the user of the equipment. One such example is providing a disposable film assemblage with its own fresh battery thereby relieving the user of the task of having to remember to replace the camera's battery at certain intervals. This type of film assemblage includes a film cassette containing a battery and a stack of sheet-like members including several film units. A wall of the film cassette is provided with a pair of apertures to which the terminals of the battery are adapted to be aligned with in order that the contacts of a camera may extend into the apertures and electrically engage the battery terminals. However, exposing the battery terminals in this manner creates a situation wherein an electrical circuit may be accidently established across the battery terminals after the film cassette containing the battery is removed from the camera. To obviate this problem several solutions have been proposed. In U.S. Pat. No. 3,798,669 the proposal entails covering the apertures of the film cassette with masks which are displacable by the camera's contacts upon the loading of the film cassette into the camera. Another proposal, set forth in U.S. Pat. No. 3,988,755, involves the positioning of an insulation strip within the film cassette, which strip is automatically moved out of its insulating position upon insertion of the film cassette into the camera and returns it to its original insulating position upon removal of the film cassette from the camera. But, since the user no longer has to remember to replace the battery, he now may have a tendency to forget it completely. Accordingly, he may, after exposing all of the film units in the film cassette, place the camera containing the film-less cassette in the closet for a prolonged period of time. During this period of inactivity, the battery may develop a leak thereby releasing corrosive materials which may seep through the apertures in the film cassette and run onto the contacts in the camera. Obviously, if this leakage is not noticed in time, the camera contacts will be damaged. Therefore, it is not only important to seal off the apertures in the cassette prior to its removal from a camera; it is also beneficial to seal these apertures substantially immediately after the last film unit within the film cassette has been exposed and removed from the film cassette during a photographic exposure cycle.